[New Build] First Build Gaming/Media Player 800-1000

I've never build a computer before but my friend has and is willing to help me put something together. Although, I want to learn more about it and get other opinions on what parts I should purchase. I like having options!

Approximate Purchase Date: Within the next few weeks

Budget Range: 800-1000 After Shipping

System Usage from Most to Least Important: 'Casual gaming' The Sims 3, Simcity, media player

Are you buying a monitor: I'm hoping to use my television which is a LG 32LG30D http://www.lg.com/au/tv-audio-video/televisions/LG-lcd-... if not I have some spare monitors around

Do you need to buy OS: Yes

Preferred Website(s) for Parts: Not sure at he moment but at least somewhere that will do reasonable shipping to Australia

Location: Adelaide, South Australia

Parts Preferences: I need more knowledge before I could answer this.

Overclocking: No

SLI or Crossfire: I honestly don't know.

Your Monitor Resolution: 1024x768

Additional Comments: I'd like something that will run my Sims games (Sims 3 and all expansions, Sims Medieval, SimCity) flawlessly and be reasonably quiet. I'd also like to use it as a media player to play my dvds/blurays. I do have a mouse and keyboard though if I have enough room in my budget I may go after wireless ones.

I'll appreciate any and all help. I'm really not sure how much I should aim to spend on certain parts.